I have had the fungus gnats in the past, but other than using sticky traps to get the adults, I haven't done anything to kill the larvae. I have not noticed any ill effects on the seedlings. I beleive there are some companies that sell some type of predator mite that preys on the larvae.

Mark

OK Thanks
Sticky Traps it is....
NC

I water the soil with Bt (Bacillus Thuringiensis). I buy something called Mosquito Dunks which are used in ponds to kill larva. I soak a piece in a jug of water and use that to water the plants. I don't know what the brands would be in the UK but I'm sure it's sold there. It doesn't affect the adult gnats but the larva are what damage the plant roots. I've also tried putting a layer of fine sand over the top of the soil which seems to help. The gnats thrive in moisture. If you can allow the soil to dry some you shouldn't have as much of a problem.
Karyn

Here we have a place called Nature's Control where we can get the good bugs. I've used 'em several times & while quite a bit slower than "death from a bottle" there's no chance of damaging yourself or killing the plants with some chemical.

I checked, they've got fungus gnat predators.. So if we have such here there's got to be a place in the UK you can find the same. Maybe even shoot 'em an email as being in the industry they might know of a place "over there".

Thanks karyn1 and krstofer
I'll go lookie at the link now
NC

Krstofer I use beneficial insects for pest control, mainly ladybugs, lacewings and mantises. There's a few mite specific predators that I'm aware of but I didn't know there were any predators for fungus gnats. Thanks, I'll have to take a look.
Karyn